<script>

function SetColor(name,value)

{

    var oDiv=document.getElementById('div3');

    oDiv.style[name]=value;

}

</script>

<input type="button" value="变宽啊"  onclick="SetColor('width','500px')"   />

<input type="button" value="变高啊"  onclick="SetColor('height','500px')"/>

<input type="button"  value="变颜色啊"  onclick="SetColor('background','green')"/>

<div id="div3">啊啊</div>